I`m trying to program Lego Mindstorm by leJos. I use Kubuntu in VM. I have 2 Lego bricks. The firmwares are accordingly 0.9.0 and 1.31. The code is written in Eclipse is running on 0.9.0 but not in 1.31. I want to downgrade the second brick. How can I do it? Thank you.

I think you mixing up two different version numbers and products here. The 1.31 firmware is the standard Lego firmware, 0.9.0 is the leJOS firmware. What is it that you are trying to do? are you running Java code on your robot, or are you using the remote version of the leJOS API to run code on your PC that controls your robot?

Hi,As I said before you are confusing two different sets of firmware. To use leJOS you must install the leJOS firmware using the nxjflash command. The leJOS firmware version is 0.9.0 0.9.1 etc. If you want to use the Lego software then you must install the Lego firmware this has version 1.03, 1.31 etc. These are two tatally different firmware products and are no related to each other. So the leJOS 0.9.0 firmware is not a downgrade from the Lego 1.03 firmware it is a totally different product. It is a little like saying I have firefox 14 how to I downgrade it to Internet Explorer 9.0...